Transportation of infants and babies in bicycle trailers is not readily possible, because the bicycle trailer seats are not designed for this. Due to the lack of suitable solutions for this problem, infant seats designed for use in cars are often placed in bicycle trailers and attached therein with belts. While an infant can, in principle, be transported in a bicycle trailer in such manner, this has the distinct disadvantage that infant car seats are very bulky and generally wider than the area of the seat provided for one child. This is particularly problematic with bicycle trailers with two seats, since once the car seat is placed in the bicycle trailers, there is hardly any room left for a second child, let alone a second infant car seat.
The only option available on the market for transporting babies in a bicycle trailer is a hard polystyrene infant seat made by the German manufacturer Weber Technik Werkzeugbau GmbH, which contrary to the aforementioned car seats has been tailored to the width of the child seat of a bicycle trailer. This carrier has a concave reclining seat area, the bottom area of which is flattened out opposite the back and shoulder area. It has a passage opening in the center just below the bottom area as well as several pairs of passage openings on both sides of the central vertical axis in the shoulder area for the belts of a restraint system. In addition, there are fastener openings in the upper and lower area of the carrier, through which the belts of a bicycle trailer seat can be threaded in order to attach the carrier.
This carrier, too, has some distinct disadvantages. It is bulky, which makes fastening the carrier in a bicycle trailer seat difficult and does not allow for space-saving storage, for instance in a warehouse or a garage. The carrier is rigid so that it does not adapt to the position and movement of a baby or infant. Finally, the carrier is not breathable, which is particularly uncomfortable on warm days or when sitting in the carrier for an extended period of time.